The holistic processing of price comparison: behavioral and electrophysiological evidences.

Although considerable studies have investigated the cognitive mechanism and the neural basis of number processing, it is unclear how numbers are represented in the practical context such as price comparison. In the present study, participants were asked to judge whether the target prices with different units (yuan, jiao, fen) were "higher or lower than 5 jiao" while event-related potentials were recorded. The behavioral results did not reveal a main effect of distance when distance was defined in terms of the digits of prices. However, a significant effect of distance was found when distance was defined in terms of the whole magnitude of prices. The electrophysiological results revealed similar distance effects (DE) during the 350-450 ms interval after stimulus onset, with an enhanced positivity for far distance than for close distance. These findings suggest that the digits and the units of prices are processed holistically rather than separately during a price comparison task.